Today blood treatment apparatuses are used for extracorporeal blood treatment which involves withdrawing blood from a patient, treating the blood and returning the treated blood to the patient. For this purpose an extracorporeal blood flow circuit (blood line) is used which is connected to a blood vessel access of the patient, typically via one or more access devices such as needles or catheters inserted into a blood vessel of the patient. Depending on method of blood treatment, the blood may be withdrawn from the patient, passed through a blood treatment unit (e.g. dialyzer) and returned to the patient via the same or another blood vessel access device. Simultaneously a fluid line withdraws a treatment fluid (i.e. fresh dialysis fluid) from a fluid source, passes the treatment fluid through the blood treatment unit where the blood is treated, and disposes used/spent treatment fluid to a drain. Extracorporeal blood treatment includes hemodialysis, hemodiafiltration, hemofiltration etc.
During blood treatment it is important that a patient is not exposed to harmful microorganisms. For this reason, new and sterile blood treatment units and bloodlines are typically used for each blood treatment session. Non-disposable parts, such as the fluid line, are typically disinfected on a regular basis to prevent microbial growth therein. Parts in contact with blood, such as the blood line and the blood treatment unit, are usually replaced with new ones when a new patient shall be treated but in some cases, the blood treatment unit and the blood line may be reused for treatment of the same patient at a later time.
Such extended use requires cleaning and disinfection of blood-contacting parts between blood treatment sessions. A number of techniques have been developed for this purpose, which typically include use of cleaning fluids, UV-radiation and/or heat for removing or killing any harmful microorganism.
A well-known cleaning solution is Renalin®, which has been used for blood treatment unit reuse for decades. It is however very harmful, and care must be taken that all Renalin® is rinsed out of the blood treatment unit before it may be used again.
One example of a cleaning technique is disclosed in U.S. Pat. No. 6,146,536 where a hemodialyzer apparatus comprises a reusable dialyzer membrane as well as reusable blood flow path and dialysis flow path units. The apparatus automatically primes itself and makes dialysis solution from dry chemicals, concentrates, and fresh water which is provided to the apparatus. After use, the apparatus automatically prepares a cleaning and rinsing solution for the cleaning and rinsing of the dialyzer membrane as well as the dialyzate and blood flow path means.
Another example of cleaning technique is given by U.S. Pat. No. 6,022,512 disclosing a cleaning and disinfecting method for treating the surfaces of hemodialysis equipment that are exposed to a dialysate or purified water. The method comprises the use of electrolyzed hyperacidity water for cleaning and disinfection.
Known techniques are generally capable of cleaning a blood line or a fluid line of a blood treatment apparatus such that various components may be reused. However, it is believed that present cleaning techniques may be improved in the sense that required hardware components and/or use of cleaning solutions may be reduced, while still safeguarding a patient from harmful microorganisms and toxic substances and allowing extended use of components.